Vehicle-track dynamic interaction considering temperature-frequency dependent viscoelastic properties of rail pads at low temperatures

Rail pads are installed between rails and sleepers via fastening systems to protect sleepers in slab-track structures from wear and impact induced by moving trains. Due to the viscoelastic nature of rubber materials, the dynamic stiffness of rail pads depends on both temperature and loading frequency. In this study, a temperature- and frequency-dependent viscoelastic (TFDV) model is proposed to describe the dynamic behavior of rail pads at low temperatures, with material parameters determined through experimental measurements. The proposed model allows accurate simulation of rail pad behavior in vehicle-track dynamic systems under coupled temperature and frequency effects. Results show that at low temperatures, rubber materials exhibit pronounced hardening, which amplifies wheel-rail contact forces and shifts dominant frequencies to higher values. Consequently, the vibration damping of rail pads is significantly reduced, leading to increased transmission of impact loads through the fastening system.